Vapor chamber structure with improved wick and method for manufacturing the same

ABSTRACT

A vapor chamber structure includes a casing, a working fluid, and an improved wick layer. The casing has an airtight vacuum chamber. The working fluid is filled into the airtight vacuum chamber. The wick layer is formed on a surface of the airtight vacuum chamber. Therefore, the present invention can increase the backflow velocity of the working fluid and improve the boiling of the working fluid due to the match of the improved wick structure. Because the backflow velocity and boiling of the working fluid is increased, the heat-transmitting efficiency is increased.

RELATED APPLICATIONS

This application is a Divisional patent application of co-pendingapplication Ser. No. 11/878,809, filed on 27 Jul. 2007. The entiredisclosure of the prior application Ser. No. 11/878,809, from which anoath or declaration is supplied, is considered a part of the disclosureof the accompanying Divisional application and is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vapor chamber structure and a methodfor manufacturing the same, and particularly relates to a vapor chamberstructure having an improved wick and a method for manufacturing thesame.

2. Description of the Related Art

Cooling or heat removal has been one of the major obstacles of theelectronic industry. The heat dissipation increases with the scale ofintegration, the demand for higher performance, and the increase ofmulti-functional applications. The development of high performance heattransfer devices becomes one of the major development efforts of theindustry.

A heat sink is often used for removing the heat from the device or fromthe system to the ambient. The performance of a heat sink ischaracterized by the thermal resistance with a lower value representinga higher performance level. This thermal resistance generally consistsof the heat-spreading resistance within the heat sink and the convectiveresistance between the heat sink surface and the ambient environment. Tominimize the heat-spreading resistance, highly conductive materials,e.g. copper and aluminum, are typically used to make the heat sink.However, this conductive heat transfer through solid materials isgenerally insufficient to meet the higher cooling requirements of newerelectronic devices. Thus, more efficient mechanisms have been developedand evaluated, and the vapor chamber has been one of those commonlyconsidered mechanisms.

Vapor chambers make use of the heat pipe principle in which heat iscarried by the evaporated working fluid and is spread by the vapor flow.The vapor eventually condenses over the cool surfaces, and, as a result,the heat is distributed from the evaporation surface (the interface withthe heat source) to the condensation surfaces (the cooling surfaces). Ifthe area of the cooling surfaces is much higher than the evaporatingsurface, the spreading of heat can be achieved effectively since thephase change (liquid-vapor-liquid) mechanism occurs near isothermalconditions.

Referring to FIG. 1, the prior art provides a vapor chamber 9 that hasan airtight casing 90. Moreover, the casing 90 is made of metal materialand has a hollow portion 900. The air in the hollow portion 900 ispumped away, and a working fluid (not shown) is filled into the hollowportion 900. The casing 90 has a wick structure 91 formed on an internalwall thereof. The chamber 9 is evacuated and charged with the workingfluid, such as distilled water, which boils at normal operatingtemperatures. External to the vapor chamber 9 there is a heat-generatingsource 92. As the heat-generating source 92 dissipates heat it causesthe working fluid to boil and evaporate. The resultant vapor (as theupward arrows) travels to the cooler section of the chamber 9 which inthis case is a top where an optional finned structure 93 is located. Atthis point the vapor condenses giving off its latent heat energy. Thecondensed fluid (as the downward arrows) now returns down through thewick structure 91 to the bottom of the chamber 9 nearest theheat-generating source 92 where a new cycle occurs.

In the prior art, the chamber 9 uses only a simple wick structure 91 toreturn the condensed fluid by capillary force and to help initiateboiling of the working fluid. A simple wick structure is difficult tooptimize for both boiling initiation and fluid flow by capillary forceand thus the overall thermal performance of the vapor chamber islimited.

Furthermore the backflow efficiency (ability to return the working fluidto the evaporator portion of the vapor chamber) of the working fluid islimited.

SUMMARY OF THE INVENTION

One particular aspect of the present invention is to provide a vaporchamber structure and a method for manufacturing the same. The vaporchamber structure of the present invention has improved thermalperformance due to the usage of at least one improved wick structure.

In order to achieve the above-mentioned aspects, the present inventionprovides a vapor chamber structure, comprising: a casing, a workingfluid, and one or more improved wick layers or backflow acceleratingbodies. The casing has an airtight vacuum chamber. The working fluid isfilled into the airtight vacuum chamber. The wick layer is formed on asurface of the airtight vacuum chamber.

In order to achieve the above-mentioned aspects, the present inventionprovides a method for manufacturing a vapor chamber structure,comprising: providing a casing that is composed of one or more uppercasings and one or more lower casings; forming one or more improvedwicks on an internal surface of the casing; assembling the uppercasing(s) and the lower casing(s) together to form a receiving chamber;pumping away air from the receiving chamber to form an airtight vacuumchamber; and then filling a working fluid into the airtight vacuumchamber and sealing the casing.

Therefore, the present invention can improve the thermal performance ofthe vapor chamber due to the use of the improved wick structures.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed. Otheradvantages and features of the invention will be apparent from thefollowing description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The various objects and advantages of the present invention will be morereadily understood from the following detailed description when read inconjunction with the appended drawings, in which:

FIG. 1 is a cross-sectional, schematic view of a vapor chamber structureof the prior art;

FIG. 2 is a perspective, exploded view of a vapor chamber structureaccording to the first embodiment of the present invention;

FIG. 3 is a perspective, assembled view of a vapor chamber structureaccording to the first embodiment of the present invention;

FIG. 4 is a cross-sectional view along line 4-4 of a vapor chamberstructure shown in FIG. 3;

FIG. 5 is a cross-sectional view along line 5-5 of a vapor chamberstructure shown in FIG. 3,

FIG. 6 is a cross-sectional, schematic view of a vapor chamber with awick that is discontinuous along the casing surface in one or moreareas,

FIG. 7 is a schematic view of a structure strengthening body composed ofa solid post and an outer wick layer,

FIG. 8 is a schematic view of structure strengthening body composed ofan outer metal solid layer and an inner wick layer,

FIG. 9A is a top view of a vapor chamber with a series of channels, somebeing micro-channels (width less than 200 microns) whose main purpose itto promote or nucleate boiling of the working fluid and some beingchannels (width greater than 200 microns) whose main purpose is topromote condensed fluid return flow from condensing areas of the vaporchamber to evaporating areas of the vapor chamber,

FIG. 9B is a cross-section view of a vapor chamber with a series ofchannels, some being micro-channels (width less than 200 microns) whosemain purpose it to promote or nucleate boiling of the working fluid andsome being channels (width greater than 200 microns) whose main purposeis to promote condensed fluid return flow from condensing areas of thevapor chamber to evaporating areas of the vapor chamber,

FIG. 10 is a cross-sectional, schematic view of a vapor chamber havingone or more channels in a casing, such channels overlaid by a wickmaterial that also contacts the casing. The wick elements are of such asize or structure such that they do not fill the channels,

FIG. 10A shows a detail feature of a portion of FIG. 10,

FIG. 11 is a cross-sectional, schematic view of a vapor chamber havingone or more channels in a casing, such channels filled by a first wickmaterial and overlaid by a second wick material that also contacts thecasing,

FIG. 11A shows a detail feature of a portion of FIG. 11,

FIG. 12 is a cross-section, schematic view of a vapor chamber having awick structure that varies in thickness on the condenser side of thechamber—being thinner at the location with the longest working fluidtravel path from heat source (typically the central portion) and thickerat the location with the shortest working fluid travel path from theheat source (typically the peripheral portion),

FIG. 13 is a cross-section, schematic view of a vapor chamber having awick structure that varies in thickness on the condenser side of thechamber—being thinner at the location with the longest working fluidtravel path from heat source (typically the central portion) and thickerat the location with the shortest working fluid travel path from theheat source (typically the peripheral portion), and including one ormore channels within the wick structure to further promote fluid flow,

FIG. 14 is a cross-section, schematic view of a vapor chamber having awick structure that varies in thickness on the evaporator side of thechamber—being thicker near the heat source (typically the centralportion) and thinner away from the heat source (typically the peripheralportion), and optionally including one or more channels within the wickstructure to further promote fluid flow

FIG. 15 is a top view of a vapor chamber having a wick structure thatvaries in a patch-wise manner,

FIG. 15A is a cross-section view of a vapor chamber having a wickstructure that varies in a patch-wise manner,

FIG. 16 is a schematic view of a wick composed of different size metalpowders stacked with each other from the large size powder to the smallsize powder;

FIG. 17 is a schematic view of a wick composed of different size metalpowders stacked with each other from the small size powders to largesize powers;

FIG. 18 is a cross-section, schematic view of a vapor chamber with wickformed from a continuous or step-wise continuous gradient of wickmaterial,

FIG. 19 is a cross-section, schematic view of a vapor chamber having amulti-layered wick structure,

FIG. 20 is a top view of a vapor chamber having a multi-layered andpatterned wick structure,

FIG. 20A is a cross-section view of a vapor chamber having amulti-layered and patterned wick structure,

FIG. 21 is a cross-section, schematic view of a vapor chamber having acomplex wick structure formed by a plurality of wick cluster elements,each cluster being formed from two or more distinct types of wickmaterials (such as two different powder sizes),

FIG. 21A is a detail feature of a portion of FIG. 21,

FIG. 22 is a top view of a vapor chamber with two or more types ofwicks, such wicks interdigitated with each other in the plan directionwhere they meet each other to promote better fluid flow between the twotypes of wicks,

FIG. 22A is a cross-section view of a vapor chamber with two or moretypes of wicks, such wicks interdigitated with each other in the plandirection where they meet each other to promote better fluid flowbetween the two types of wicks,

FIG. 23 is a top view of a vapor chamber two or more types of wicks,such wicks interdigitated with each other in the height direction wherethey meet each other to promote better fluid flow between the two typesof wicks,

FIG. 23A is a cross-section view of a vapor chamber two or more types ofwicks, such wicks interdigitated with each other in the height directionwhere they meet each other to promote better fluid flow between the twotypes of wicks,

FIG. 24 is a top view of a vapor chamber having one or moresubstantially radial wick geometries,

FIG. 24A is a cross-section view of a vapor chamber having one or moresubstantially radial wick geometries,

FIG. 25 is a top view of a vapor chamber having one or moresubstantially circular or ovoid wick geometries,

FIG. 25A is a cross-section view of a vapor chamber having one or moresubstantially circular or ovoid wick geometries,

FIG. 26 is an isometric, schematic view of a vapor chamber that includesone or more extended surfaces, configured as protrusions on one or moreof the casings,

FIG. 27 is an isometric, schematic view of a vapor chamber that includesone or more extended surfaces, configured as depressions or pits in oneor more of the casings,

FIG. 28 is a cross-section, schematic view a vapor chamber where thewick completely fills the chamber,

FIG. 29 is a cross-section, schematic view of a vapor chamber where themulti-layered wick completely fills the chamber,

FIG. 30 is a cross-section, schematic view of a wick for a vapor chambercontaining at least some wick elements that are preferentially coated ontheir exterior surface to promote easier joining of the wick to thecasing or to each other,

FIG. 30A shows a detail feature of portion B of FIG. 30,

FIG. 31 is a top view schematic of a pre-fabricated vapor chamber wick,

FIG. 31A is a cross-section view schematic of a pre-fabricated vaporchamber wick,

FIG. 32 is a top view of a pre-fabricated, multi-layer vapor chamberwick,

FIG. 32A is a cross-section view of a pre-fabricated, multi-layer vaporchamber wick,

FIG. 33 is a flowchart of a method for manufacturing a vapor chamberstructure of one embodiment of the present invention,

FIG. 34A is a top view of the first step of a method for manufacturing amulti-layer wick on to a vapor chamber casing,

FIG. 34 a is a cross-section view of the first step of a method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34B is a top view of the second step of a method for manufacturinga multi-layer wick on to a vapor chamber casing,

FIG. 34 b is a cross-section view of the second step of a method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34C is a top view of the third step of a method for manufacturing amulti-layer wick on to a vapor chamber casing,

FIG. 34 c is a cross-section view of the third step of a method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34D is a cross-section view of the fourth step of a method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35A is a top view of the first step of another method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35 a is a cross-section view of the first step of another methodfor manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35B is a top view of the second step of another method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35 b is a cross-section view of the second step of another methodfor manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35C is a top view of the third step of another method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35 c is a cross-section view of the third step of another methodfor manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35D is a top view of the fourth step of another method formanufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35 d is a cross-section view of the fourth step of another methodfor manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35E is a cross-section view of a vapor chamber by affixing apre-fabricated wick structure to one or more casings of a vapor chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2 to 5, the first embodiment of the present inventionprovides a vapor chamber structure 1 a, comprising: a casing 10, aworking fluid 20, a wick layer 12, and at least one structurestrengthening bodies 13.

The casing 10 has an airtight vacuum chamber 100, and the working fluid20 is filled into the airtight vacuum chamber 100. The casing 10 iscomposed of an upper casing 101 and a lower casing 102 that mates withthe upper casing 101. Moreover, the casing 10 has contact surfacesbetween the upper casing 101 and the lower casing 102. The contactsurfaces have a predetermined width, in order to assemble the uppercasing 101 and the lower casing 102 easily.

Furthermore, the vapor chamber structure further comprises at least onefilling pipe 15 communicated with the airtight vacuum chamber 100 via ajoint opening 103 of the casing 10 (in FIG. 2, a filling pipe 15 isshown). The filling pipe 15 has an opening side 151 formed on one sidethereof and a closed side 152 formed on the other side thereof. Thefilling pipe 15 is arranged at the periphery of the casing 10 (e.g. acorner). Hence, before the closed side 152 of the filling pipe 15 issealed, the working fluid 20 can be guided via the filling pipe 15 andbe filled into a receiving chamber that is composed of the upper casing101 and the lower casing 102. Moreover, the air in the receiving chamberis pumped away and the closed side 152 of the filling pipe 15 is sealed,so that the receiving chamber becomes the airtight vacuum chamber 100.

In order to increase the matching between the filling pipe 15 and thejoint opening 103 of the casing 10, a contact surface between the casing10 and the filling pipe 15 has a length L larger than a double length ofa diameter D of the filling pipe 15 (L>2D as shown in FIG. 5).Furthermore, in order to increase the surfaces in contact in the jointarea the filling pipe 15 can have an ovoid or other non-circularcross-section. The location of the filling pipe 15 with respect to theperiphery of the top casings can be also fixed by features on thefilling pipe (e.g. a rib or groove) that mate to corresponding featureson the casing.

The wick layer 12 is formed on an internal surface of the airtightvacuum chamber 100. The wick layer 12 is made of metal powders via asintering method, or is composed of metal meshes or micro grooves orother materials or geometries that are conducive to enhancing the flowof the working fluid due to capillary forces. Another function of thewick structure is to promote and enhance boiling of the working fluidadjacent to the heat input areas.

The structure strengthening bodies 13 are respectively arranged in theairtight vacuum chamber 100 and between the upper casing 101 and thelower casing 102 for supporting the casing 10. In the first embodiment,each structure strengthening body 13 can be a solid post, made of copperor any solid material with high thermal conductivity and high strength.Moreover, the structure strengthening bodies 13 are concentrated in acenter position (the position of the casing 10 is fragile and isdeformed easily) of the airtight vacuum chamber 100. Hence, although thecasing 10 is pressed inward during a vacuum-pumping process, the casing10 can still maintain its surface planarization on a top surface and abottom surface thereof due to the support of the structure strengtheningbodies 13. Therefore, the casing 10 can compactly contact with aheat-generating source (not shown) for increasing heat-transmittingeffect between the heat-generating source and the vapor chamberstructure 1 a.

In the same principle, because the vapor chamber structure 1 a alwaysneeds to perform heat-absorbing action and heat-releasing action, thecasing 10 expands when hot and shrinks when cold. However, in thepresent invention, the casing 10 can still maintain its surfaceplanarization on the top surface and the bottom surface thereof due tothe support of the structure strengthening bodies 13.

Furthermore, the vapor chamber structure 1 a comprises at least onebackflow accelerating body 14. The backflow accelerating bodies 14 arerespectively arranged in the airtight vacuum chamber 100 and between theupper casing 101 and the lower casing 102 for increasing the backflowvelocity of the working fluid 20 because that each backflow acceleratingbody 14 is a flow path for the backflow of the working fluid 20 (asshown in FIG. 4). Each backflow accelerating body 14 can be a metalpowder post that is formed via a sintering method. Furthermore, thebackflow accelerating bodies 14 are dispersed to peripheral positions orother positions that are preferential to the backflow path of thecondensed and relatively cold working fluid of the airtight vacuumchamber 100. Referring to FIGS. 7 and 8, according to the designer'sneed, each structure strengthening body 13′ can be composed of a solidpost 130′ and a wick layer 131′ circumferentially covering an externalsurface of the solid post 130′. Each backflow accelerating body 14′ canbe composed of a wick post 140′ and a metal solid layer 141′ coveredcircumferentially on an external surface of the wick post 140′. The wickcan be fabricated with any suitable process and materials—to include butnot be limited to metal powders, meshes, or small grooves on the surfaceof the structural strengthening element. However, the structurestrengthening body 13 and the backflow accelerating body 14 are notshown in following drawings.

Referring to FIG. 6, a wick 12 is dispersed on one or more of thecasings in a discontinuous fashion and at least one separated portion ofthe wick 16 are disposed to isolate the wick layer 12. The wick layercan be preferentially placed in those areas that will most benefit byits presence (e.g. for nucleating boiling at the evaporator or promotingworking fluid return flow to the evaporator in other locations), and canpreferentially remain absent in those areas that would have little to nobenefit from the presence of the wick. In this way the usage of wickmaterial can be minimized and the fabrication process simplifiedresulting in higher assembly yield. For example, in some cases a wickmay only be required on the bottom casing 102 and not the top casing 101(not shown).

Referring to FIGS. 9A and 9B, a vapor chamber with a series of channelsformed in the casing, some being micro-channels 18 (width less than 200microns) whose main purpose is to promote or nucleate boiling of theworking fluid and some being channels 17 (width greater than 200microns) whose main purpose is to promote condensed fluid return flowfrom condensing areas of the vapor chamber to evaporating areas of thevapor chamber. These channels may be arranged and arrayed in any fashionrequired to serve the purpose of nucleating boiling at one or morelocations in the vapor chamber and to serve the purpose of returningworking fluid 20 to the evaporator from one or more condensing locationsin the vapor chamber. Furthermore, the micro-channels 18 and channels 17can have features that promote or control the fluid flow within them,such as the channels being of varying width along their length, thechannels being of varying depth along their length or the channelshaving varying surface textures along their length. These features canbe combined in any combination to achieve the desired fluid flowresults.

Referring to FIGS. 10 and 10A, a vapor chamber having at least onechannel 17 in a casing 10 is provided, such channels 17 overlaid by awick layer 12′ formed by a plurality of second wick elements that alsocontacts the casing 10. The wick layer 12 is formed by a plurality offirst wick elements. The second wick elements are of such a size orstructure different from the first wick element such that they do notfill the channels 17, thereby keeping the channels open for fluid flow.

Referring to FIGS. 11 and 11A, a vapor chamber having at least onechannel 17 in a casing 10 is provided, such channels filled by a firstwick element of the wick layer 12 and overlaid by a second wick layer12′ that also contacts the casing 10. The second wick elements 122 ofwick 12′ are of such a size or structure that they do not fill thechannels 17, whereas the elements 120 of wick layer 12 are of such asize that they do fill the channels 17. The wick layer 12 and itselements 120 are chosen not only to be able to fill the channels 17 butto promote either fluid flow in the channels 17 or nucleate boiling inthe channels 17 in the evaporator region.

Referring to FIG. 12, the vapor chamber 10 has a wick structure thatvaries in thickness on the condenser side of the chamber (in this caseon the top casing 101)—being thinner at the location with the longestworking fluid travel path from the heat source (typically the centralportion) and thicker at the location with the shortest working fluidtravel path from the heat source (typically the peripheral portion). Thevarying wick thickness will promote varying levels of capillary forceand therefore fluid flow, such that the wick can be thicker andtherefore provide higher fluid flow in those areas that would benefitfrom higher flow and vice versa can be thinner and provide less flow inthose areas that require less flow.

Referring to FIG. 13, the vapor chamber 10 has a wick structure thatvaries in thickness on the condenser side of the chamber (in this caseon the top casing 101)—being thinner at the location with the longestworking fluid travel path from the heat source (typically the centralportion) and thicker at the location with the shortest working fluidtravel path from the heat source (typically the peripheral portion). Thevarying wick thickness will promote varying levels of capillary forceand therefore fluid flow, such that the wick can be thicker andtherefore provide higher fluid flow in those areas that would benefitfrom higher flow and vice versa can be thinner and provide less flow inthose areas that require less flow. Furthermore the wick structure 12has micro-channels 18 formed into it to further promote fluid flow.

Referring to FIG. 14, the vapor chamber 10 has a wick structure thatvaries in thickness on the evaporator side of the chamber (in this caseon the bottom casing 102)—being thicker at the location with theshortest working fluid travel path from the heat source (typically thecentral portion) and thinner at the location with the longest workingfluid travel path from the heat source (typically the peripheralportion). The varying wick thickness will promote varying levels ofcapillary force and therefore fluid flow, such that the wick can bethicker and therefore provide higher fluid flow in those areas thatwould benefit from higher flow and vice versa can be thinner and provideless flow in those areas that require less flow. Furthermore the wickstructure 12 can include optional flow micro-channels 18 that furtherpromote fluid flow.

Referring to FIGS. 15 and 15A, there is provided a vapor chamber havinga wick structure that varies in a patch-wise manner. The wick iscomposed of two or more wick structures, such as 12 and 12′, with eachpreferentially placed in predetermined areas or patches that takeadvantage of the particular features and benefits of those wickstructures. For example, a patch or patches composed of a wick structure12′ optimized for nucleate boiling might be located on the evaporatorareas of the vapor chamber while a patch or patches composed of a wickstructure 12 optimized for fluid flow might be located on the condenserareas and between the condenser and evaporating areas of the vaporchamber.

Referring to FIG. 16, a vapor chamber is provided that utilizes a wick12 composed of different size elements stacked with each other from thelarge size elements 122 to the small size elements 120. Although powdersare depicted, it will be understood that other appropriate wickstructures (e.g. wire mesh) could likewise be arranged in this fashion.

Referring to FIG. 17, a vapor chamber is provided that utilizes a wick12 composed of different size elements stacked with each other from thesmall size elements 120 to large size elements 122. Although powders aredepicted, it will be understood that other appropriate wick structures(e.g. wire mesh) could likewise be arranged in this fashion.

Referring to FIG. 18, a vapor chamber with wick 12 formed from acontinuous or step-wise continuous gradient of wick material isprovided. For example, the wick can be composed of elements of varyingsize from small sized elements 120, to intermediate sized elements 121,to larger sized elements 122. The gradients can be arranged in anyfashion (increasing or decreasing element size with distance) or inmultiple areas to achieve the boiling and fluid flow properties desired.

Referring to FIG. 19, a vapor chamber is provided having a multi-layeredwick structure, composed of at least one layers of a first wick type 12and at least one layers of a second wick type 12′. In this embodiment,one layers of a second wick type 12′ is disposed between the two layersof a first wick type 12 to from a sandwich-like structure contacted withthe bottom casing 102. The layers are formed by wicks of varyingproperties, depicted here as alternating layers of wick 12 and wick 12′,although the number of types, number of layers, thickness and otherfeatures of such wicks will be designed to yield the desired functionand performance of the wicks in the vapor chamber.

Referring to FIGS. 20 and 20A, a vapor chamber is provided having amulti-layered and patterned wick structure, composed of two or more wickstructures 12 and 12′, layered one over the other, and with areas thatmay be patterned in certain shapes or structures. Furthermore there maybe means of communicating from a layer of one wick type 12 to anotherlayer of similar wick type 12 by way of a fluid accelerating body 14.The layers are formed by wicks of varying properties, depicted here asalternating layers of wick 12 and wick 12′, although the number,thickness and other features of such wicks will be designed to yield thedesired function and performance of the wicks in the vapor chamber.

Referring to FIGS. 21 and 21A, a vapor chamber is provided having acomplex wick structure 40 formed by a plurality of wick cluster elements410, each cluster 410 being formed from two or more distinct types ofwick materials (such as two different powder sizes 411 and 412). Betweenand among the powder particles or other wick elements (e.g. wire mesh orother) there are pores or open spaces of generally a small size, whilebetween and among the clusters 410 there are relatively large pores oropen spaces 413. Thus this wick structure 40 can provide a complexlyvarying type and amount and size of pores or open spaces, which can beoptimized to promote boiling in some regions and capillary fluid returnflow in other areas. Furthermore the complex wick structure 40 can becombined in use with a less complex wick structure 12 within the samevapor chamber. The complex wick structure 40 can also be provided withattributes as previously described elsewhere in this invention—such asconfiguration patches or variation in thickness or inter-digitation withother wick structures, or any and all of the previously describedstructures or applications.

Referring to FIGS. 22 and 22A, a vapor chamber is provided having two ormore types of wicks 12 and 12′, such wicks interdigitated with eachother in the plan direction where they meet each other to promote betterfluid flow between the two or more types of wicks. Such wicks may alsobe a combination of both powder materials and wire mesh materials.

Referring to FIGS. 23 and 23A, a vapor chamber is provided having two ormore types of wicks 12 and 12′, such wicks interdigitated with eachother in the height direction where they meet each other to promotebetter fluid flow between the two or more types of wicks. Such wicks mayalso be a combination of both powder materials and wire mesh materials.

Referring to FIGS. 24 and 24A, a vapor chamber is provided having one ormore substantially radial wick geometries 12′. The radial wick 12′ isembedded in the wick 12 to form the wick structure.

Referring to FIGS. 25 and 25A, a vapor chamber is provided having one ormore substantially circular or ovoid wick geometries 12 and 12′.

Referring to FIG. 26, a vapor chamber is provided that includes at leastone extended surface, configured as protrusions 104 having predeterminedheight from one or more of the casings 10. The extended surface, coatedwith the wick 12, provides additional surface area to promote boilingand evaporation on those parts of the vapor chamber adjacent to the heatsource and likewise an extended surface will improve the heat transferon the condensing portions of the vapor chamber (not shown), thusimproving the thermal efficiency of the vapor chamber.

Referring to FIG. 27, a vapor chamber is provided that includes one ormore extended surfaces, configured as depressions or pits or channels 17in one or more of the casings 10. The extended surface, coated with thewick 12, provides additional surface area to promote boiling andevaporation on those parts of the vapor chamber adjacent to the heatsource and likewise an extended surface will improve the heat transferon the condensing portions of the vapor chamber (not shown), thusimproving the thermal efficiency of the vapor chamber.

Referring to FIG. 28, a vapor chamber is provided where the wick element12 completely fills the vacuum chamber 100 between the casings 101 and102 to form the wick layer 12. In this case the wick material itself isable to strengthen the vapor chamber and allow it to support a muchhigher applied load or force than a vapor chamber with some amount ofempty, unfilled space in the vacuum chamber 100.

Referring to FIG. 29, a vapor chamber is provided where a multi-layeredwick completely fills the vacuum chamber 100 to form a sandwich-likestructure between the casings 101 and 102. In this case the wickelements themselves are able to strengthen the vapor chamber and allowit to support a much higher applied load or force than a vapor chamberwith some amount of empty, unfilled space in the vacuum chamber 100. Thelayers are formed by wicks of varying properties, depicted here asalternating layers of wick 12 and wick 12′, although the number,thickness and other features of such wicks will be designed to yield thedesired function and performance of the wicks in the vapor chamber.

Referring to FIGS. 30 and 30A, a vapor chamber is provided containing awick 12 where at least some wick elements 121 are preferentially coatedon their exterior surface by a coating layer 124 to promote easierjoining of the wick to the casing 102 or of the wick elements 121 tothemselves. For example a Nickel-Phosphorous coating on copper wickelements could help promote and accelerate the sintering or diffusionbonding of those elements to each other or to a casing 102, such casingtypically made of brass, copper or steel.

Referring to FIGS. 31 and 31A, a pre-fabricated vapor chamber wick isprovided. A wick layer 12 can be pre-fabricated outside and apart fromthe vapor chamber. The wick layer can integrally include features suchas channels 17, protrusions 126, and holes 125. A prefabricated wick canalso include any and all of the features or elements noted elsewhere inthis disclosure for wicks fabricated within the vapor chamber. Forexample the figure shows solid structural strengthening elements 13(both adhered to an outer surface of the wick or embedded in a hole inthe wick) or porous fluid accelerating bodies 14, or other features orelements not shown in the figure such as gradient wick elements,patch-wise wick structures and the like. Furthermore, the wick layeritself may be patterned in such fashion as to promote fluid boiling,condensation or fluid flow depending on the wick function required atvarious locations within the vapor chamber.

Referring to FIGS. 32 and 32A, a pre-fabricated, multi-layer vaporchamber wick is provided. Two or more wick layers, composed of two ormore types of wick elements (e.g. 12 and 12′) are stacked one atop theother. Such layers also may include other features such as holes orchannels (not shown) or porous fluid accelerating bodies 14—with theoption of including or not including any of the features previouslymentioned in this invention on any layer. Furthermore, each wick layeritself may be patterned in such fashion as to promote fluid boiling,condensation or fluid flow depending on the wick function required atvarious locations within the vapor chamber—as shown in the plan views.Finally the number of wick layers and their thickness and the type ofwick element used within each layer will also be chosen to promote fluidflow or nucleate boiling as required within the vapor chamber.

Referring to FIG. 33, the present invention provides a method formanufacturing a vapor chamber structure of one embodiment of the presentinvention. The method comprises providing a casing 10 that is composedof an upper casing 101 and a lower casing 102 (S101); forming a wicklayer 12 on an internal surface of the casing 10 (S102) and thenrespectively arranging a plurality of structure strengthening bodies 13and a plurality of backflow accelerating bodies 14 between the uppercasing 101 and the lower casing 102 (S103). The manufacturing steps S102and S103 can be alternatively replaced. As shown in FIG. 33, after S101,a plurality of structures are first arranged (S103′) and then forming awick layer on the internal surface (S102′).

The method further comprises assembling the upper casing 101 and thelower casing 102 together to form a receiving chamber (S104); pumpingaway air from the receiving chamber to form an airtight vacuum chamber100 (S105) and then filling a working fluid 20 into the airtight vacuumchamber 100 and sealing the casing 10 (S106).

Referring to FIGS. 34 a-34 c and 34A-34D, a series of drawings depictinga method for manufacturing a multi-layer wick on to a vapor chambercasing 10 is provided. In this method a first wick layer 12 is depositedon the casing 102 (S111), such layer also may include other featuressuch as holes or channels (not shown) or porous fluid acceleratingbodies 14. Then a second wick layer 12′ is deposited over the first wicklayer (S113), such second wick layer also may include other featuressuch as holes or fluid accelerating bodies (not shown) or channels 17.Subsequently a third wick layer 12 and a fourth wick layer 12′ aredeposited (S115)—with the option of including or not including any ofthe features previously mentioned (fluid accelerating bodies, channels,holes and the like). Furthermore, each wick layer itself may bepatterned in such fashion as to promote fluid boiling, condensation orfluid flow depending on the wick function required at various locationswithin the vapor chamber—as shown in the plan views. Finally the numberof wick layers and their thickness will also be chosen to promote fluidflow or nucleate boiling as required within the vapor chamber. Then, theupper casing 101 and the lower casing 102 are assembled together (S117).

Referring to FIGS. 35 a-35 d and 35A-35E, a series of drawings showingthe sequence of steps in the manufacture of a pre-fabricated,multi-layer wick for a vapor chamber is provided. In this method a firstwick layer 12 is fabricated (S211), such layer also may include otherfeatures such as holes or channels (not shown) or porous fluidaccelerating bodies 14. Then a second wick layer 12′ is deposited overthe first wick layer (S212), such second wick layer also may includeother features such as holes or fluid accelerating bodies (not shown) orchannels 17. Subsequently a third wick layer 12 and a fourth wick layer12′ are deposited (S213)—with the option of including or not includingany of the features previously mentioned (fluid accelerating bodies,channels, holes and the like). Furthermore, each wick layer itself maybe patterned in such fashion as to promote fluid boiling, condensationor fluid flow depending on the wick function required at variouslocations within the vapor chamber—as shown in the plan views. Finallythe number of wick layers and their thickness and the type of wickelements within each wick layer will also be chosen to promote fluidflow or nucleate boiling as required within the vapor chamber.

FIG. 35E is a cross-section view of a vapor chamber by affixing apre-fabricated wick structure to one or more casings of a vapor chamber.First, to dispose the multi-layer wick inside the lower casing 102(S215) and then the upper casing 101 and the lower casing 102 areassembled together (S217). In conclusion, the vapor chamber structure ofthe present invention has capabilities as a backflow acceleratingfunction and improved boiling function due to the usage of backflowaccelerating bodies 14 or improved wick structures 12. Therefore, thepresent invention can increase the backflow velocity of the workingfluid 20 and the boiling of the working fluid due to the match backflowaccelerating bodies 14 and improved wick structures 12. Because thebackflow velocity of the working fluid 20 is increased and the boilingfunction is improved, the heat-transmitting efficiency is increased.

Although the present invention has been described with reference to thepreferred best methods thereof, it will be understood that the inventionis not limited to the details thereof. Various substitutions andmodifications have been suggested in the foregoing description, andothers will occur to those of ordinary skill in the art. Therefore, allsuch substitutions and modifications are intended to be embraced withinthe scope of the invention as defined in the appended claims.

1. The method for manufacturing a pre-fabricated improved wick outsideand apart from the vapor chamber, such wick layer formed by a pluralityof wick elements adjoined to each other such that they create acontinuous, porous layer.
 2. The method as claimed in claim 1 whereinthe joining method for the wick elements is by a high temperatureprocess over 350 degrees Celsius.
 3. The method as claimed in claim 2wherein the joining method is chosen from sintering, diffusion bonding,copper-copper oxide eutectic bonding, or brazing.
 4. The method asclaimed in claim 1 wherein the method reduces the wick layer thicknessin certain locations.
 5. The method as claimed in claim 4 wherein wickelements are reduced in number or eliminated in those areas of reducedwick layer thickness.
 6. The method as claimed in claim 5 whereinadjoined wick elements are compressed in those areas of reduced wicklayer thickness.
 7. The method as claimed in claim 1 wherein the methodincreases the wick layer thickness in certain locations.
 8. The methodas claimed in claim 7 wherein wick elements are increased in number inthose areas of increased wick layer thickness.
 9. The method as claimedin claim 1 wherein the method includes the addition of structurestrengthening bodies to the wick layer in certain locations.
 10. Themethod as claimed in claim 1 wherein the method includes the addition ofbackflow accelerating bodies to the wick layer in certain locations. 11.The method as claimed in claim 1 wherein the method includes bending orforming the wick layer in certain locations.
 12. The method as claimedin claim 1 wherein the method includes the use of wick elements ofdifferent sizes or types.
 13. The method as claimed in claim 12 whereinthe method includes arranging certain of the wick elements by size ortype within certain areas of the wick.
 14. The method as claimed inclaim 13 wherein the method arranges wick elements by size in thevertical direction with either the smallest elements on top orconversely with the largest elements on top to form a piece-wisecontinuous or continuous gradient of wick element sizes.
 15. The methodas claimed in claim 13 wherein the method arranges wick elements by sizein the plan or horizontal direction from elements of smaller to largersize to form a piece-wise continuous or continuous gradient of wickelement sizes.
 16. The method as claimed in claim 13 wherein the methodarranges wick elements of different sizes or types in multiple layers,with at least one layer of one size or type of wick element and anotherlayer of a second size or type of wick element.
 17. The method asclaimed in claim 16 wherein the method arranges wick elements ofdifferent sizes or types in multiple layers, with at least one layer ofone size or type of wick element and another layer of a second size ortype of wick element, and also provides communication or a via incertain locations from a first wick layer to a third wick layer throughan intervening second wick layer.
 18. The method as claimed in claim 13wherein the method arranges wick elements of different sizes or typessuch that one or more patches of a wick element of one size or type arearranged within a field of substantially a wick element of a second sizeor type.
 19. The method as claimed in claim 18 wherein the methodarranges wick elements of different sizes or types such that more thanone patches of a wick element of one size or type are arranged within afield of substantially a wick element of a second size or type, andthere is a communication between the wick elements of the first size ortype.
 20. The method as claimed in claim 19 wherein the method providescommunication between patches by creating pathways between patches ofthe same wick element that forms the patches.
 21. The method as claimedin claim 19 wherein the method provides communication between patches byusing wick elements of a third type or by no wick elements at all tocreate the communication pathways, as distinguished from using the firstwick elements or the second wick elements.
 22. The method as claimed inclaim 13 wherein the method arranges wick elements of different sizes ortypes both in multiple layers and with patches of wick elements ofdifferent sizes or types within a field comprised of wick elements of adifferent size or type within certain layers, and providing forcommunication between patches within layers horizontally and forcommunication between layers vertically, such method consisting of thestructured arrangement of wick elements of different sizes or types incertain locations starting with a first layer and subsequently addingadditional layers one atop the other with the structured arrangement ofwick elements of different sizes or types in certain locations on eachsubsequent layer.